1. Field of Invention
This invention relates to a coating device and method. More particularly, this invention relates to a coating device and method for coating a film with more than two kinds of thickness.
2. Related Art
A coating process has been used extensively in the metal processing, semiconductor, optoelectronics, and other related industries. Continual advances in the semiconductor and optoelectronics industries have resulted in the rapid development of new coating technology processes.
However, coating a film with more than two kinds of thickness on a substrate, in particular, with a specific gradual change slope, has been difficult to achieve.
Previously, a typical coating method for coating a film with more than two different thicknesses in different sections on a substrate is tilting the substrate during the coating process. FIG. 1 is a schematic simplified diagram of a typical coating device 4. With reference to FIG. 1, a target 42 for sputtering or vacuum evaporation is put on a base 41, and a substrate 43 is set above the base 41. In this case, the substrate 43 is set above the base 41 with a tilting angle. Herein, the thickness of the coating film 5 is in an inverse proportion as the 1.5th to 2nd order of the distance between the base 41 and the substrate 43. Therefore, the thickness of a portion of the substrate 43 is as thick as substrate 43 is close to the base 41.
Although the tilting angle creates a gradient thickness on the substrate, it can't define a gradient slope at a specific point on the substrate. When the substrate is tilted at an angle, the gradient slope is pre-determined, and prevents coating the coating film with the desired specific gradual change slope.